An electric vehicle and/or a plug-in hybrid vehicle have mounted thereon an inverter device that drives a motor with a high-voltage battery for power drive and a low-voltage battery for operating auxiliary machines, such as a light and a radio of the vehicle. Such a vehicle has mounted thereon a DC/DC converter device (power conversion device) that performs the power conversion from a high-voltage battery to a low-voltage battery or the power conversion from a low-voltage battery to a high-voltage battery.
Some power conversion devices have coupled thereto filter circuits, such as an input filter circuit on the input side of a power conversion circuit and an output filter circuit on the output side of the power conversion circuit, as one of the purposes for reducing noise that mixes into an electronic device and the like arranged outside the power conversion device (e.g., see Patent Literature 1).